It wasn’t much more than a ghost house by the time Rufus McDonald got the call.

The front door of the abandoned home near 75th and Sangamon was unlocked and swinging in the wind.

Drug addicts, squatters and stray animals carried away whatever they wanted. Everything that wasn’t termite-infested seemed to have been stolen. Even the copper pipes were gone.

But the scavengers missed something incredible.

Hidden in the attic that McDonald was contracted to clear before the home’s 2009 demolition was a trunk. Inside were the papers of Richard T. Greener, the first African American to graduate from Harvard.

“I didn’t know who he was,” said McDonald, 51. “But as soon as I found out, I knew this was a story that had to be told.”

Historians thought the documents were lost in the 1906 San Francisco earthquake because Greener had passed through at the time. They were astonished to learn in the past week that Greener’s 1870 Harvard diploma — water-damaged but intact — his law license, photos and papers connected to his diplomatic role in Russia and his friendship with President Ulysses S. Grant have survived.

His graduation blazed a trail for black Harvard intellectuals including Gates’ friend, President Barack Obama, the professor added. “He was the voice before DuBois and the president’s predecessor.”

Declined money on the spot

When McDonald found the steamer trunk in the Englewood attic, he suspected the contents inside were important but wasn’t sure.

The presence of the 1853 book Autographs for Freedom inside added to the intrigue.

Members of his clean-out crew told him to throw the heavy trunk and its contents away.

McDonald knew better.

He packed up the documents in a brown-paper bag and hauled them out of the house, bringing them to a book expert on the North Side.

“Do you know who Richard Greener was?” McDonald was asked. When he told him he didn’t, the expert explained Greener’s importance.

McDonald was offered money for the documents on the spot, but he declined.

He went back to the Englewood home, hoping to retrieve the steamer trunk. By then, however, not only was the trunk gone, so was the entire house. Demolished.

How the documents got to the Englewood attic is a question that might never be answered. Greener lived the final years of his life with cousins in Hyde Park. But there’s no evidence he ever lived in the Englewood home, which is nearly six miles away.

Sadness in personal life

If Greener’s importance as a “black first” and his public roles as a brilliant attorney, scholar, diplomat and orator devoted to racial equality secure his place in history, his private life was tainted by sadness, historians say.

Though Greener was helped by a handful of whites, he was resented by some blacks and was trapped under a glass ceiling that prevented him from becoming a more significant figure, they add. The discovery could encourage a fresh look at his legacy.

Born to the son of a slave in Philadelphia in 1844, he left school at 14 and became a porter at a Boston hotel.

A pair of white businessmen took him under their wing and helped him enroll at Harvard in 1865.

Harvard admitted him as “an experiment,” according to historian Michael Mounter, who wrote a Ph.D. thesis on Greener. Greener initially struggled but eventually thrived. He made allies including U.S. Sen. Charles Sumner and won prizes for public speaking and essays.

In 1873, he was appointed professor of philosophy at the University of South Carolina. He dodged an assassination attempt by a “red shirt” at an 1876 rally, but lost his job a year later when racist Democrats were elected.

Became law school dean

Married to Genevieve Ida Fleet, with whom he had six children, he became dean of Howard University’s law school; worked at the U.S. Treasury and in Republican politics and law in Washington, and befriended President Ulysses S. Grant, whose memorial he helped build.

A friend and sometimes rival of other leading African Americans of his era, including Frederick Douglass and Booker T. Washington, he wrote in 1879: “The negro has received so many hard knocks, and experienced so little consideration, charity, or justice from those who criticize him, that he has no quarter to give.”

In an 1894 essay he pointedly renamed the “Negro Problem” as “The White Problem.”

Sick of Washington politics, in 1898 he accepted a post from President William McKinley in Vladivostok, Russia. Leaving his family, he took a Japanese common-law wife, Mishi Kawashima, with whom he had three children. He was praised for his efforts as a U.S. agent during the Russo-Japanese war, but he was fired in 1905 after a smear campaign.

From 1909 until his death in 1922 he lived with cousins at 5237 S. Ellis in Chicago. Cut off from both his families, he was likely visited just once in Hyde Park by his daughter Belle da Costa Greene, according to biographer Heidi Ardizzone.

Along with the rest of Greener’s first family, da Costa Greene — the chic director of banker J.P. Morgan’s personal library — changed her last name to pass as white in elite New York society. “Greener had so much intelligence and passion and to see his equally talented children not have their achievements counted as African American must have been heartbreaking,” Ardizzone said.

Da Costa Greene burned her own personal papers before her death in 1950. The discovery of some of her father’s documents in an Englewood attic is “every historian’s dream,” Ardizzone said.

McDonald “is to be commended” for his discovery, Gates added.

Harvard would love documents

Harvard, the DuSable Museum of African American History, the Pierpont Morgan Library, the Black Metropolis Research Consortium and Greener’s granddaughter from his second marriage, Evelyn Bausman, 75, of Connecticut, all are interested in the documents. Bausman called the find “amazing.”

Gates — known for his 2009 “beer summit” on the White House lawn with President Obama and a Cambridge cop who arrested him on his own doorstep — says he would “love to bring the artifacts to Harvard.” He said he would offer “a fair price” but warned McDonald not to expect to get rich.

McDonald’s own education ended when he graduated from Calumet High School. But he says his research into the story behind the documents has made him proud of Greener’s story.

“You have to wonder, if Greener hadn’t graduated from Harvard, would Obama have gone to law school there?” he said. “Would Obama be president?”